Cloches
Cloches are mainly used to protect crops in the vegetable garden, although they are just as useful for protecting plants and seedlings during cold weather. There are a wide variety of cloches available, from bell jars and lantern cloches to protect individual plants to low tunnels or tent cloches that protect a row of crops.
Materials
Glass is the best (and most expensive) material, as it has excellent light transmission and allows the frame to warm up quickly in the sun. Clear plastic material is a cheaper alternative, but does not retain as much heat or allow such good light penetration.
Single thickness plastic is the cheapest of the plastic cloches, ranging in thickness from 150-800 gauge. As it does not retain heat well, plastic sheeting is useful when providing protection for plants where high temperatures are not necessary. PVC and polypropylene are thicker and more rigid and can be moulded into corrugated sheets or individual shapes. They both retain heat better than plastic sheeting, but not as well as glass or twin-walled polycarbonate, which offers good insulation and should last for ten years or more.
Cloche Styles
Tunnel Cloche
This style of cloche is typically used to protect crops, and is usually made from a series of wire hoops covered with heavy-duty, flexible plastic. Alternatively, rigid tunnel models are available; although these are more expensive than flexible plastic, they are generally more attractive and are much easier to move around, as they do not need to be dismantled.
Tent Cloche
This cloche is suitable for low-growing plants or for protecting young seedlings. It may be constructed easily using two sheets of glass to form a tent shape.
Barn Cloche
As its name suggests, this cloche is shaped like a barn or a house, with 4 vertical sides supporting a sloping, tent-shaped top. Its additional height makes it handy for taller plants. They are usually constructed from glass or rigid plastic, often with removable or lifting tops to provide ventilation and easy access for maintenance and harvesting.
Individual Cloche
These small cloches are used to protect individual vulnerable plants, either in the early stages of growth or during adverse weather such as heavy rain, high winds, snow or frost. Purpose-built models are available to buy, but cheap, homemade versions can also be constructed from waxed-paper or cut-off plastic bottles.
Floating Cloche
Also known as a floating mulch, a floating cloche is made up of a sheet of polypropylene fibre fleece or perforated plastic sheeting secured over sown crops or even individual plants. The sheets allow air and water to pass freely through to the plants and soil below, but provide valuable insulating properties.